The invention herein pertains to replaceable air filters and particularly pertains to an adjustable frame used to maintain air filters in place in air passageways.
Many heating and air conditioning systems in homes, office buildings and the like utilize replaceable air filters for collection of dust, pollen, debris and the like. These replaceable filters usually employ fiberglass strands contained by a cardboard edging. As such they are relatively inexpensive and are somewhat flimsy in construction. Most heating and air conditioning manufacturers recommend the air filters be changed once a month to ensure proper system operation and to provide the necessary filtering capacity. Standard filters come in a variety of lengths and widths, generally measured in inches with a standard thickness of one inch. While other sizes, thicknesses and dimensions are used, the one inch thickness is recognized as an industry standard.
Also, xe2x80x9cnon-wovenxe2x80x9d fabrics have been devised which are of a relatively stiff nature and require no outer frame, as opposed to fiberglass filters which have a relatively stiff paper outer edge. Regardless of the type of conventional filter used, homeowners, building managers and maintenance men and the like have all experienced filters being dislodged from the filter xe2x80x9cseatxe2x80x9d in the ductwork and drawn or forced along the ductwork to a corner or other location thus requiring manual extraction. Inadvertent dislodgement of the filter allows air to flow without filtering and can create mechanical problems to the air system and health problems to the individuals affected.
The reason for accidental filter dislodgement is often a direct result of the flimsy nature of conventional air filters. As a filter becomes loaded, the air pressure increases on the face of the filter, oftentimes allowing the air stream to carry or remove the filter from its usual seat. Other times conventional air filters are incorrectly installed and are dislocated on system startup or operation.
Thus, based on the problems and disadvantages with seating conventional air filters, it is an objective of the present invention to provide an air filter frame and method which will allow a filter to securely remain in its designated seat within the ductwork of a conventional air handling system.
It is another objective of the invention to provide an air filter frame that requires no tools and which is easy to use and install in the ductwork seat.
It is yet another objective of the invention to provide an air filter frame which can be manufactured which will adjustably contain a number of different size air filters as required.
It is still another objective of the invention to provide an air filter frame which has first and second sections which slidably engage for adjustment purposes.
It is a further objective of the invention to provide an air filter frame which is relatively light in weight and inexpensive to manufacture and distribute.
Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed description is set forth below.
The aforementioned and other objectives are realized by providing an air filter frame and method for use formed from a suitable metal such as aluminum, a rigid paper, polymeric material, or combination thereof. The filter frame includes a first section having a rectangular planar back having a plurality of apertures therein. Attached along the edges of the back are sidewalls and an endwall. An upright guide is positioned on the back which is contained within a slot of an upper or second section. The second section likewise includes a rectangular planar back which is sized to fit between the side walls of the first section. The defined guide slot partially extends along the length of the second section and contains the guide. As the slot does not extend the entire length of the second section, when the second section is fully extended from the first section, the end of the slot contacts the guide and terminates the relative movement between the sections, thus preventing the first and second sections from complete disengagement. The back of the second section likewise contains a plurality of circular apertures and an end wall. The second section end wall is in an opposing relation to the first section end wall when the two sections are engaged. The ends and side walls of both sections are at a height to contain the air filter placed therein. By selecting a filter of sufficient width, to fit within the filter frame, the length of the filter frame can be slideably adjusted to accommodate the length of the filter. The method of use includes the steps of placing a conventional filter within the frame, adjusting the frame to the length of the filter by sliding the first and second sections to first an open position for filter placement and then to close the frame to tightly engage the filter therein. Thereafter the filter and frame combination can be placed in an air duct filter seat of a heating or air conditioning system. The frame will stabilize the filter and prevent it from dislodging from its seated position.